Changeset 55155

Timestamp:

01/27/2023 10:12:37 PM (4 years ago)

Author:

flixos90

Message:

Editor: Use a non-persistent object cache in wp_get_global_settings().

This changeset is part of a greater effort to enhance the caching strategy for theme.json based data. Similar to [55138] and [55148], the cache is currently ignored when WP_DEBUG is on to avoid interrupting the theme developer's workflow.

This addition of a non-persistent cache results in a significant performance improvement for the overall load time of WordPress, with the Server-Timing load metric being ~8% faster and Time to First Byte being 25+% faster than before.

Props oandregal, spacedmonkey, hellofromtonya, flixos90, azaozz, aristath.
Fixes #57502.

File:

• trunk/src/wp-includes/global-styles-and-settings.php (modified) (2 diffs)

trunk/src/wp-includes/global-styles-and-settings.php

@@ -26 +26 @@
 function wp_get_global_settings( $path = array(), $context = array() ) {
         if ( ! empty( $context['block_name'] ) ) {
-                $path = array_merge( array( 'blocks', $context['block_name'] ), $path );
-        }
-
+                $new_path = array( 'blocks', $context['block_name'] );
+                foreach ( $path as $subpath ) {
+                        $new_path[] = $subpath;
+                }
+                $path = $new_path;
+        }
+
+        /*
+         * This is the default value when no origin is provided or when it is 'all'.
+         *
+         * The $origin is used as part of the cache key. Changes here need to account
+         * for clearing the cache appropriately.
+         */
         $origin = 'custom';
-        if ( isset( $context['origin'] ) && 'base' === $context['origin'] ) {
+        if (
+                ! wp_theme_has_theme_json() ||
+                ( isset( $context['origin'] ) && 'base' === $context['origin'] )
+        ) {
                 $origin = 'theme';
         }
 
-        $settings = WP_Theme_JSON_Resolver::get_merged_data( $origin )->get_settings();
+        /*
+         * By using the 'theme_json' group, this data is marked to be non-persistent across requests.
+         * See `wp_cache_add_non_persistent_groups` in src/wp-includes/load.php and other places.
+         *
+         * The rationale for this is to make sure derived data from theme.json
+         * is always fresh from the potential modifications done via hooks
+         * that can use dynamic data (modify the stylesheet depending on some option,
+         * settings depending on user permissions, etc.).
+         * See some of the existing hooks to modify theme.json behaviour:
+         * https://make.wordpress.org/core/2022/10/10/filters-for-theme-json-data/
+         *
+         * A different alternative considered was to invalidate the cache upon certain
+         * events such as options add/update/delete, user meta, etc.
+         * It was judged not enough, hence this approach.
+         * See https://github.com/WordPress/gutenberg/pull/45372
+         */
+        $cache_group = 'theme_json';
+        $cache_key   = 'wp_get_global_settings_' . $origin;
+
+        /*
+         * Ignore cache when `WP_DEBUG` is enabled, so it doesn't interfere with the theme
+         * developer's workflow.
+         *
+         * @todo Replace `WP_DEBUG` once an "in development mode" check is available in Core.
+         */
+        $can_use_cached = ! WP_DEBUG;
+
+        $settings = false;
+        if ( $can_use_cached ) {
+                $settings = wp_cache_get( $cache_key, $cache_group );
+        }
+
+        if ( false === $settings ) {
+                $settings = WP_Theme_JSON_Resolver::get_merged_data( $origin )->get_settings();
+                if ( $can_use_cached ) {
+                        wp_cache_set( $cache_key, $settings, $cache_group );
+                }
+        }
 
         return _wp_array_get( $settings, $path, $settings );
@@ -318 +368 @@
 function wp_clean_theme_json_cache() {
         wp_cache_delete( 'wp_get_global_stylesheet', 'theme_json' );
+        wp_cache_delete( 'wp_get_global_settings_custom', 'theme_json' );
+        wp_cache_delete( 'wp_get_global_settings_theme', 'theme_json' );
         WP_Theme_JSON_Resolver::clean_cached_data();
 }